The brass fixture is something that makes me wonder also. It looks more like 19th century. What was the purpose of these plugs ? Were they to be exchanged for a fuze in normal artillery projectiles ? The tubes inside the shell make no sense as a war-projectile. Already in the 18th century "Fire Stone" or "Rock Fire" and "Valenciennes Composition"(US terminology around 1859) "Geschmolzenzeug"(german terminology) was a standard incendiary composition and the Best available in black powder times. These were used up till the end of the 19th century as broken chunks mixed up with the bursting charge powder.Besides the incendiary effect on any burnable matter, it also had a good anti personnel effect because the burning chunks stuck to clothes and continued burning. This is 18th century "Napalm". The tubes would be a waste of the little available space inside a projectile. In Germany (which did not exist as a state then), more precisely in Prussia (in other states like Hannover it was the same) it was the artillery that manufactured all ammunition in their own laboratories (Spandau / Berlin) as well as fireworks. The artillery also displayed the fireworks up till around the end of the 18th century. In historical usage a FEUERWERKER was a pyrotechnician, an EOD man , a munitions manufacturer and an artillerist, all in personal union. Every new recruit, after his apprenticeship training had to manufacture a full complement of fireworks items and to display them as well as some military ammunition. Only after passing this test he became a full fledged artillerist. I assume that this state of affairs was the same in england in the 17th/18th century. I have never seen a construction like in the fotos mentioned in 19th century literature. In the 17th century there existed constructions, but with metallic tubes inside, which contained on top of some plack powder a metal projectile. The effect was the intermittent firing of small projectiles after the shell had landed somewhere. Not very effective. I do not know the history of the royal laboratory, but expect it's development to be similar to Prussian developments. Because of this, ammunition for war and fireworks for amusement often looked very much similar. Also a fireworks shell had to be projected from a mortar. Only the effect of the shell makes it a war-store or a fireworks shell for amusement. So even the RL stamp is no proof of this being a war-ammunition-item. For a definite answer one would have to examine the item, first under a microscope. This would give definite answers on the type of materials used (paper, parchment, leather, wood, type of metal). As a pyrotechnician I would examine the construction and content of the inside of the tubes. If anybody here knows of any 18th/19th century literature with descriptions of projectiles similar to ones pictured above, I would be grateful for any hint.
regards,
Bellifortis.
